The present disclosure relates to electric tools for impacting in orthopedic applications, and, more particularly, to an electric motor driven tool for orthopedic impacting that is capable of providing controlled impacts to a broach, chisel, or other device for creating an opening in an area (in a bone structure, for example) to securely receive prosthesis within the area.
In the field of orthopedics, prosthetic devices such as artificial joints, are often implanted or seated in a patient's body by seating the prosthetic device in a cavity of a bone of the patient. The cavity must be created before the prosthesis is seated or implanted, and traditionally, a physician may remove worn, excess, or diseased bone structure from the area in which the cavity will be formed, and then drill and hollow out a cavity along the medullar canal of the bone. A prosthesis usually includes a stem or other protrusion that serves as the particular portion of the prosthesis that is inserted into the cavity.
To create such a cavity, a physician may use a broach, which broach conforms to the shape of the stem of the prosthesis. Solutions known in the art include providing a handle with the broach, which handle the physician may grasp while hammering the broach into the implant area. Unfortunately, this approach is clumsy and unpredictable as being subject to the skill of the particular physician. This approach almost will always inevitably result in inaccuracies in the location and configuration of the cavity. Further, this approach carries with it the risk that the physician will damage bone structure in unintended areas.
Another technique for creating the prosthetic cavity is to drive the broach pneumatically, that is, by compressed air. This approach is disadvantageous in that it prevents portability of an impacting tool, for instance, because of the presence of a tethering air line, air being exhausted from a tool into the sterile operating field and fatigue of the physician operating the tool. Further this approach, as exemplified in U.S. Pat. No. 5,057,112 does not allow for precise control of the impact force or frequency and instead functions very much like a jackhammer when actuated. Again, this lack of any measure of precise control makes accurate broaching of the cavity more difficult.
Another disadvantage of tools known in the art is the accumulation of fluids, such as body fluids or moisture, on handgrips of such tools during prolonged periods of use. For example, difficulty of operation of a broach impacting device known in the art may increase during a surgical procedure as handgrips may become saturated with bodily fluids and thus the physician's hold on such a prior art device may become impaired.
Consequently, there exists a need for an impacting tool that overcomes the various disadvantages in the prior art.
In view of the foregoing disadvantages of the prior art, an electric motor-driven orthopedic impacting tool configured to include all the advantages of the prior art, and to overcome the drawbacks inherent therein is provided. The tool may be used by orthopedic surgeons for orthopedic impacting in for example hips, knees, and shoulders. The tool is capable of holding a broach, chisel, or other device and gently tapping the broach, chisel or other device into the cavity with controlled percussive impacts, resulting in a better fit for the prosthesis or the implant. Further, the control afforded by such an electrically manipulated broach, chisel, or other device allows adjustment of the impact settings according to a particular bone type or other profile of a patient. The tool additionally enables proper seating or removal of the prosthesis or the implant into or out of an implant cavity.
In an embodiment, an electric motor-driven orthopedic impacting tool comprises a control unit, a housing, a linear motion converter, at least one reducing gear, an impacting element (also referred to herein as a striker), an air chamber, a compression piston, and a force adjustment control means (hereinafter referred to as ‘control means’). The tool may further include a motor, an LED, a handle portion with at least one handgrip for comfortable gripping the tool, a broach adapter, a battery, a feedback system and a nose-piece for the broach adapter. At least some of the various components are preferably contained within the housing. The tool is capable of applying cyclic impact forces on a broach, chisel, or other device, or an implant and of finely tuning impact force to a plurality of levels of impact force.
In an embodiment, the tool further comprises a control means, which means includes a force adjustment element, and which element may control the impact force and avoid damage caused by uncontrolled impacts.
The tool further comprises an anvil element, which anvil element includes both a forward and rearward point of impact and a guide that constrains the striker to move in a substantially axial direction. In operation, the movement of the striker along the guide of the anvil element continues in either a forward or rearward direction until the striker hits the point of impact. As used in this context, “forward direction” connotes movement of the striker toward a broach or patient, and “rearward direction” connotes movement of the striker away from the broach or chisel or patient. If the impact point is at the front of the tool, i.e., in a forward direction, the impact causes the percussive force to be transmitted to a broach or chisel, pushing it further into the cavity. If the impact point is at the rear of the tool, the percussive force tends to pull the broach or chisel out of the cavity. The selectivity of either bidirectional or unidirectional impacting provides flexibility to a surgeon in either cutting or compressing material within the implant cavity, in that the choice of material removal or material compaction is often a critical decision in a surgical procedure. The impact point may be in the form of a plate that is disposed at an end or each end of the anvil element.
The tool is further capable of regulating the frequency of the striker. By regulating the frequency of the striker, the tool may impart a greater total time-weighted percussive impact, while maintaining the same impact magnitude. This allows for the surgeon to control the cutting speed of the broach or chisel. For example, the surgeon may choose cutting at a faster rate (higher frequency impacting) during the bulk of the broach or chisel movement and then slow the cutting rate as the broach or chisel approaches a desired depth.
A user may firmly hold the tool by the handle portion and utilize light emitted by the LED to light up a work area and accurately position the broach, chisel, or other device on a desired location on the prosthesis or the implant. The reciprocating movement imparted on broach, chisel, or other device causes tapping of the implant and/or broach, chisel, or other device and thereby enables proper seating or removal of a prosthesis or implant into or out of an implant cavity, or controlled impacting of a broach, chisel, or other device to create or shape an implant cavity. The tool may also include a feedback system that warns the surgeon, when a bending or off-line orientation beyond a certain magnitude is detected at a broach, chisel, or other device/implant interface.
These together with other aspects of the present disclosure, along with the various features of novelty that characterize the present disclosure, is pointed out with particularity in the claims annexed hereto and forms a part of this present disclosure. For a better understanding of the present disclosure, its operating advantages, and the specific objects attained by its uses, reference should be made to the accompanying drawing and descriptive matter in which there are illustrated exemplary embodiments of the present disclosure.
Like references numerals refer to like parts throughout the description of several views of the drawings.